1. Field of the Invention
This invention relates generally to mining and more particularly to processing a sized ore feed.
2. Description of Related Art
Surface mining operations are generally employed to excavate an ore deposit that is found near the surface. Such ore deposits are usually covered by an overburden of rock, soil, and/or plant matter, which may be removed prior to commencing mining operations. The remaining ore deposit may then be excavated and transported to a plant for processing to remove commercially useful products. For example, the ore deposit may comprise an oil sand deposit from which hydrocarbon products may be extracted.
In the example of an oil sand ore deposit, such as the Northern Alberta Tar Sands, the ore deposit comprises about 70 to about 90 percent by weight of mineral solids including sand and clay, about 1 to about 10 percent by weight of water, and a bitumen or oil film. The bitumen may be present in amounts ranging from a trace amount up to as much as 20 percent by weight. Consequently, since oil sand ore deposits comprises a relatively small percentage by weight of bitumen, it is generally more efficient and cost effective to at least partially separate the bitumen from the ore as soon as possible after excavation, since significant energy costs are incurred in transporting the ore over long distances.
In commonly owned Canadian Patent Application No. 2,567,644, a process line for mining an oil sands ore body is disclosed. The process line includes an excavator for mining oil sands ore, a comminutor for receiving mined ore from the excavator and comminuting the mined ore to conveyable size and transferring the comminuted ore to a mobile conveyor for transporting the comminuted ore. The comminutor supplies conveyable ore to the mobile conveyor, and the mobile conveyor is periodically moved in an arc about a discharge end to locate another portion of the ore body within operational reach of the mobile conveyor until substantially all of the ore body within operational reach of the conveyor has been mined. In one disclosed embodiment the ore is transported to a mobile slurry facility located proximate a mine face of an oil sand deposit. Operation of the disclosed process line requires that the overburden be removed, either prior to commencing excavation or as the conveyor advances in the operational arc. Following mining of the ore deposit, the slurry facility may be relocated to a subsequent mine face for excavation of a subsequent portion of the ore body. Accordingly, the disclosed process line facilitates successively mining generally circular sectors of the ore deposit.